Fluid shut-off device

Abstract

A fluid shut-off device is provided which comprises a non-magnetic casing having a fluid passage therein, a metallic valve body movably disposed in the casing to close the passage at one operative position, and a magnetic member slidably disposed outside the casing and magnetically attracting the valve body. The magnetic member takes an inoperative position against a spring force and is locked at this position. The lock is released by a bimetallic strap deformable by supply of an electric current. When the lock is released, the magnetic member is moved by the action of the spring force, so that the valve body magnetically attracted by the magnetic member is also moved to the operative position to shut off the flow of fluid material through the passage.

What is claimed is: 
     
       1. A fluid shut-off device comprising: a casing made of non-magnetic material, said casing having therethrough a passage which is adapted to be connected with a fluid supply line, and said casing having therein a valve chamber at a mid-portion of said passage;   a valve body positioned in said valve chamber for movement between a first position to close said passage and a second position to open said passage;   a slide member provided outside said casing;   at least one of said valve body and said slide member being made of permanent magnet material and the other of said slide member and said valve body being made of magnetic material, whereby said valve body and said slide member are magnetically attracted to each other;   elastic spring means for urging said slide member toward an operative position whereat said valve body is at said first position thereof and closes said passage;   locking means for holding said slide member against the force of said spring means at an inoperative position whereat said valve body is at said second position thereof and opens said passage, said locking means comprising a metal strap having a free end bendable from a first locking position to a second unlocking position; and   means for releasing said metal strap from said first locking position thereof, said releasing means comprising a bimetallic strap deformable by supply thereto of an electric current, said bimetallic strap being provided adjacent to said metal strap to allow said free end to bend into said second unlocking position when said electric current is supplied to said bimetallic strap.   
     
     
       2. A fluid shut-off device as claimed in claim 1, wherein said slide member is an annular permanent magnet slidably mounted around said casing; and said metal strap of said locking means is connected to said casing in a cantilever manner, the free end of said metal strap being engagable with a member connected to said permanent magnet. 
     
     
       3. A fluid shut-off device as claimed in claim 1, wherein said bimetallic strap is formed in a bridge-shape over which said metal strap crosses, said metal strap being made of a leaf spring and tending to flex inwardly against said bimetallic strap, said bimetallic strap keeping said bridge-shape to hold said metal strap in said first locking position thereof at said inoperative position but being deformed by said metal strap upon application of the electric current thereto to displace said metal strap to said second unlocking position thereof. 
     
     
       4. A fluid shut-off device as claimed in claim 3, wherein said metal strap is provided with an electrically insulative material on the underside thereof to be electrically isolated from said bimetallic strap. 
     
     
       5. A fluid shut-off device as claimed in claim 1, wherein said bimetallic strap is connected to an electric power source through means for detecting leakage of the fluid, said detecting means closing a contact in a circuit to supply the electric current to said bimetallic strap. 
     
     
       6. A fluid shut-off device as claimed in claim 1, wherein said bimetallic strap is connected to an electric power source through a mercury switch.